1. Field of the Invention
The present invention relates to a device for comparing the sounds made by a drum at the time of an adjustment of the sound of the drum which is to be employed in band performances, etc.
2. Description of the Related Art
Musical instrument drums include the bass drum, floor tom, tom-tom and a snare drum with a snappy mounted on it, etc. in the order of the size of their calibers. All drums have a beatable membrane which is called the drum head. The drum head is affixed to the drum, typically in the manner shown in FIG. 18. The drum head 51 is mounted on the upper and optionally the lower edges of the drum body. A respective drum head tightening hoop 52 is placed on the outer peripheral edge of the drum head 51. Next, a tightening bolt 55 is screwed to the lug nuts 54 which have been arranged at equally spaced intervals around the drum body through a respective lug 53 on the outer periphery on the side of the drum body 50. The hoop 52 is compressively tightened, thereby fixing the drum head 51 to the drum body 50. A tuning key 56 tightens the drum head by selectively tightening each lug and its nut. In addition, the drum head 51 is evenly stretched over the entire range prior to the performance.
To tune the drum head, in the past, the area of the drum head in the neighborhood of each tightening bolt 55 for the drum head was lightly beaten with a stick 57. The high or low sound which was generated was compared with the sound in the neighborhood of the tightening bolt so that the tightening bolt might be adjusted with the tuning key so as to eliminate the difference between the high sound and the low sound.
As the performer carried out this adjusting operation while directly listening to the sound generated by the drum stick with his ears, the adjusting operation would have to be carried out in a quiet location where the sound made by the stick would not be erased by or made unclear due to the noise of the surrounding area. In addition, extreme care and caution is required for such an operation. Thus, it requires both time and skill. Since it would be extremely difficult for a layman or a performer without very sensitive hearing to adjust the drum, performances may have been presented without correct adjustment, at the present stage of development.
Current drum heads are made of a polyester film or membrane, with a thickness approximately in the range between 50 and 400 microns. The highness or lowness of the pitch of the sound generated by beating the drum head is ultimately determined by tightening the drum head by means of the tightening bolt. If there are a strongly stretched part and a weakly stretched part of the drum head, the overall sound produced would be a combination of both these sounds, which would produce an impure sound or a growling sound, which is not desirable for a drum.
Any part too tightly stretched, moreover, will lead to a durability problem, as the polyester film that constitutes the drum head may exceed the range of its elastic deformation, or go beyond its yield point and ultimately rupture.
Therefore, a device for measuring the tensile force on the drum head previously has been proposed. (See Official Gazette of Patent Kokai (Laid Open) No. Sho 57-37231). This prior art device comprises an annular base, a detecting bar which is installed freely movable in the vertical direction at the center of the base, and a dial gauge installed sideways at the top of the annular base. The annular base is placed on the surface of the drum head, the surface of the drum head is pressed upon by the detecting bar enough to cause the bar to sink in to the drum head, and the amount of the sinking in of the detecting bar is displayed on the dial gauge.
In the device just described, however, the value which is indicated by the dial gauge does not conform to the high or low sound of the drum, thereby making it difficult to use. When the location where the value of the dial gauge moves from zero to 0.4 is compared with the location where that value moves from zero to 0.8, to cite an example, the actual sound interval ratio is not 1:2 i.e. a difference of one octave, despite the fact that the dial gauge shows a ratio of 1:2. As the drum head is stretched tightly, it is difficult to indicate the high or low sounds on the dial gauge.
When a snare drum is tuned to a high pitch, therefore, the value on the dial gauge will remain unchanged even if the tightening bolt is adjusted in that tuned state. As a result, it has not been easy to evenly stretch the drum head. When a bass drum is tuned to a low pitch, on the other hand, it has been difficult to make any adjustment as the value on the dial gauge has tended to be too sensitive. This is believed to be due to the fact that the value Y, which is displayed by the dial gauge in the above device, is in the relationship of Y=1-X, as compared with the distance which the detection bar sinks into the drum head. Both the distance of the sinking in and the amount of a protrusion of the measurement element in this invention are designated X, as they are equal.